* INFO: task rcu_kthread:6 blocked for more than 120 seconds.
@ 2011-01-12 17:43 Russell King
2011-01-12 22:22 ` Paul E. McKenney
0 siblings, 1 reply; 6+ messages in thread
From: Russell King @ 2011-01-12 17:43 UTC (permalink / raw)
To: Linux Kernel List
I'm seeing rcu_kthread get stuck from time to time on ARM Versatile PB
(ARM926). Kernel is based upon commit 9e9bc973 (immediately prior to
the merge of the OMAP tree.)
~ # ps aux|grep rcu
root 6 0.0 0.0 0 0 ? S 02:31 0:01 [rcu_kthread]
root 502 9.0 0.3 3740 472 ttyAMA0 S+ 02:59 0:00 grep rcu
~ # ps aux|grep rcu
root 6 0.0 0.0 0 0 ? D 02:31 0:01 [rcu_kthread]
root 504 0.0 0.3 3740 472 ttyAMA0 S+ 03:00 0:00 grep rcu
~ # ps aux|grep rcu
root 6 0.0 0.0 0 0 ? D 02:31 0:01 [rcu_kthread]
root 506 0.0 0.3 3740 472 ttyAMA0 S+ 03:00 0:00 grep rcu
~ # ps aux|grep rcu
root 6 0.0 0.0 0 0 ? D 02:31 0:01 [rcu_kthread]
root 508 0.0 0.3 3740 472 ttyAMA0 S+ 03:00 0:00 grep rcu
~ # cat /proc/6/wchan
rcu_kthread
~ # INFO: task rcu_kthread:6 blocked for more than 120 seconds.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
rcu_kthread D c02c6684 0 6 2 0x00000000
Backtrace:
[<c02c6388>] (schedule+0x0/0x354) from [<c00836a0>] (rcu_kthread+0x78/0xf4)
[<c0083628>] (rcu_kthread+0x0/0xf4) from [<c00633ac>] (kthread+0x88/0x90)
[<c0063324>] (kthread+0x0/0x90) from [<c004d12c>] (do_exit+0x0/0x5f8)
r7:00000013 r6:c004d12c r5:c0063324 r4:c181df28
no locks held by rcu_kthread/6.
--
Russell King
Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/
maintainer of:
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: INFO: task rcu_kthread:6 blocked for more than 120 seconds.
2011-01-12 17:43 INFO: task rcu_kthread:6 blocked for more than 120 seconds Russell King
@ 2011-01-12 22:22 ` Paul E. McKenney
2011-01-13 15:17 ` Thomas Weber
2011-01-13 20:05 ` Russell King
0 siblings, 2 replies; 6+ messages in thread
From: Paul E. McKenney @ 2011-01-12 22:22 UTC (permalink / raw)
To: Russell King; +Cc: Linux Kernel List
On Wed, Jan 12, 2011 at 05:43:00PM +0000, Russell King wrote:
> I'm seeing rcu_kthread get stuck from time to time on ARM Versatile PB
> (ARM926). Kernel is based upon commit 9e9bc973 (immediately prior to
> the merge of the OMAP tree.)
>
> ~ # ps aux|grep rcu
> root 6 0.0 0.0 0 0 ? S 02:31 0:01 [rcu_kthread]
> root 502 9.0 0.3 3740 472 ttyAMA0 S+ 02:59 0:00 grep rcu
> ~ # ps aux|grep rcu
> root 6 0.0 0.0 0 0 ? D 02:31 0:01 [rcu_kthread]
> root 504 0.0 0.3 3740 472 ttyAMA0 S+ 03:00 0:00 grep rcu
> ~ # ps aux|grep rcu
> root 6 0.0 0.0 0 0 ? D 02:31 0:01 [rcu_kthread]
> root 506 0.0 0.3 3740 472 ttyAMA0 S+ 03:00 0:00 grep rcu
> ~ # ps aux|grep rcu
> root 6 0.0 0.0 0 0 ? D 02:31 0:01 [rcu_kthread]
> root 508 0.0 0.3 3740 472 ttyAMA0 S+ 03:00 0:00 grep rcu
> ~ # cat /proc/6/wchan
> rcu_kthread
> ~ # INFO: task rcu_kthread:6 blocked for more than 120 seconds.
> "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
> rcu_kthread D c02c6684 0 6 2 0x00000000
> Backtrace:
> [<c02c6388>] (schedule+0x0/0x354) from [<c00836a0>] (rcu_kthread+0x78/0xf4)
> [<c0083628>] (rcu_kthread+0x0/0xf4) from [<c00633ac>] (kthread+0x88/0x90)
> [<c0063324>] (kthread+0x0/0x90) from [<c004d12c>] (do_exit+0x0/0x5f8)
> r7:00000013 r6:c004d12c r5:c0063324 r4:c181df28
> no locks held by rcu_kthread/6.
Does the following patch help?
Thanx, Paul
------------------------------------------------------------------------
commit 70ce43253a4465211a9c51e33d56a417c759a718
Author: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Date: Wed Jan 12 14:18:11 2011 -0800
rcu: avoid pointless blocked-task warnings
If the RCU callback-processing kthread has nothing to do, it parks in
a wait_event(). If RCU remains idle for more than two minutes, the
kernel complains about this. This commit changes from wait_event()
to wait_event_interruptible() to prevent the kernel from complaining
just because RCU is idle.
Reported-by: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
diff --git a/kernel/rcutiny.c b/kernel/rcutiny.c
index 0344937..0c343b9 100644
--- a/kernel/rcutiny.c
+++ b/kernel/rcutiny.c
@@ -189,7 +189,8 @@ static int rcu_kthread(void *arg)
unsigned long flags;
for (;;) {
- wait_event(rcu_kthread_wq, have_rcu_kthread_work != 0);
+ wait_event_interruptible(rcu_kthread_wq,
+ have_rcu_kthread_work != 0);
morework = rcu_boost();
local_irq_save(flags);
work = have_rcu_kthread_work;
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: INFO: task rcu_kthread:6 blocked for more than 120 seconds.
2011-01-12 22:22 ` Paul E. McKenney
@ 2011-01-13 15:17 ` Thomas Weber
2011-01-13 15:42 ` Paul E. McKenney
2011-01-13 20:05 ` Russell King
1 sibling, 1 reply; 6+ messages in thread
From: Thomas Weber @ 2011-01-13 15:17 UTC (permalink / raw)
To: paulmck; +Cc: Russell King, Linux Kernel List
Am 12.01.2011 23:22, schrieb Paul E. McKenney:
> On Wed, Jan 12, 2011 at 05:43:00PM +0000, Russell King wrote:
>> I'm seeing rcu_kthread get stuck from time to time on ARM Versatile PB
>> (ARM926). Kernel is based upon commit 9e9bc973 (immediately prior to
>> the merge of the OMAP tree.)
>>
>> ~ # ps aux|grep rcu
>> root 6 0.0 0.0 0 0 ? S 02:31 0:01 [rcu_kthread]
>> root 502 9.0 0.3 3740 472 ttyAMA0 S+ 02:59 0:00 grep rcu
>> ~ # ps aux|grep rcu
>> root 6 0.0 0.0 0 0 ? D 02:31 0:01 [rcu_kthread]
>> root 504 0.0 0.3 3740 472 ttyAMA0 S+ 03:00 0:00 grep rcu
>> ~ # ps aux|grep rcu
>> root 6 0.0 0.0 0 0 ? D 02:31 0:01 [rcu_kthread]
>> root 506 0.0 0.3 3740 472 ttyAMA0 S+ 03:00 0:00 grep rcu
>> ~ # ps aux|grep rcu
>> root 6 0.0 0.0 0 0 ? D 02:31 0:01 [rcu_kthread]
>> root 508 0.0 0.3 3740 472 ttyAMA0 S+ 03:00 0:00 grep rcu
>> ~ # cat /proc/6/wchan
>> rcu_kthread
>> ~ # INFO: task rcu_kthread:6 blocked for more than 120 seconds.
>> "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
>> rcu_kthread D c02c6684 0 6 2 0x00000000
>> Backtrace:
>> [<c02c6388>] (schedule+0x0/0x354) from [<c00836a0>] (rcu_kthread+0x78/0xf4)
>> [<c0083628>] (rcu_kthread+0x0/0xf4) from [<c00633ac>] (kthread+0x88/0x90)
>> [<c0063324>] (kthread+0x0/0x90) from [<c004d12c>] (do_exit+0x0/0x5f8)
>> r7:00000013 r6:c004d12c r5:c0063324 r4:c181df28
>> no locks held by rcu_kthread/6.
>
> Does the following patch help?
>
> Thanx, Paul
>
> ------------------------------------------------------------------------
>
> commit 70ce43253a4465211a9c51e33d56a417c759a718
> Author: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> Date: Wed Jan 12 14:18:11 2011 -0800
>
> rcu: avoid pointless blocked-task warnings
>
> If the RCU callback-processing kthread has nothing to do, it parks in
> a wait_event(). If RCU remains idle for more than two minutes, the
> kernel complains about this. This commit changes from wait_event()
> to wait_event_interruptible() to prevent the kernel from complaining
> just because RCU is idle.
>
> Reported-by: Russell King <rmk@arm.linux.org.uk>
> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
>
> diff --git a/kernel/rcutiny.c b/kernel/rcutiny.c
> index 0344937..0c343b9 100644
> --- a/kernel/rcutiny.c
> +++ b/kernel/rcutiny.c
> @@ -189,7 +189,8 @@ static int rcu_kthread(void *arg)
> unsigned long flags;
>
> for (;;) {
> - wait_event(rcu_kthread_wq, have_rcu_kthread_work != 0);
> + wait_event_interruptible(rcu_kthread_wq,
> + have_rcu_kthread_work != 0);
> morework = rcu_boost();
> local_irq_save(flags);
> work = have_rcu_kthread_work;
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
Hello Paul,
here it helps. Tested on Devkit8000 (omap3, beagleboard clone). Without
this patch I had permanent crashes. With this patch board is running.
Tested-by: Thomas Weber <weber@corscience.de>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: INFO: task rcu_kthread:6 blocked for more than 120 seconds.
2011-01-13 15:17 ` Thomas Weber
@ 2011-01-13 15:42 ` Paul E. McKenney
0 siblings, 0 replies; 6+ messages in thread
From: Paul E. McKenney @ 2011-01-13 15:42 UTC (permalink / raw)
To: Thomas Weber; +Cc: Russell King, Linux Kernel List
On Thu, Jan 13, 2011 at 04:17:50PM +0100, Thomas Weber wrote:
> Am 12.01.2011 23:22, schrieb Paul E. McKenney:
> > On Wed, Jan 12, 2011 at 05:43:00PM +0000, Russell King wrote:
> >> I'm seeing rcu_kthread get stuck from time to time on ARM Versatile PB
> >> (ARM926). Kernel is based upon commit 9e9bc973 (immediately prior to
> >> the merge of the OMAP tree.)
> >>
> >> ~ # ps aux|grep rcu
> >> root 6 0.0 0.0 0 0 ? S 02:31 0:01 [rcu_kthread]
> >> root 502 9.0 0.3 3740 472 ttyAMA0 S+ 02:59 0:00 grep rcu
> >> ~ # ps aux|grep rcu
> >> root 6 0.0 0.0 0 0 ? D 02:31 0:01 [rcu_kthread]
> >> root 504 0.0 0.3 3740 472 ttyAMA0 S+ 03:00 0:00 grep rcu
> >> ~ # ps aux|grep rcu
> >> root 6 0.0 0.0 0 0 ? D 02:31 0:01 [rcu_kthread]
> >> root 506 0.0 0.3 3740 472 ttyAMA0 S+ 03:00 0:00 grep rcu
> >> ~ # ps aux|grep rcu
> >> root 6 0.0 0.0 0 0 ? D 02:31 0:01 [rcu_kthread]
> >> root 508 0.0 0.3 3740 472 ttyAMA0 S+ 03:00 0:00 grep rcu
> >> ~ # cat /proc/6/wchan
> >> rcu_kthread
> >> ~ # INFO: task rcu_kthread:6 blocked for more than 120 seconds.
> >> "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
> >> rcu_kthread D c02c6684 0 6 2 0x00000000
> >> Backtrace:
> >> [<c02c6388>] (schedule+0x0/0x354) from [<c00836a0>] (rcu_kthread+0x78/0xf4)
> >> [<c0083628>] (rcu_kthread+0x0/0xf4) from [<c00633ac>] (kthread+0x88/0x90)
> >> [<c0063324>] (kthread+0x0/0x90) from [<c004d12c>] (do_exit+0x0/0x5f8)
> >> r7:00000013 r6:c004d12c r5:c0063324 r4:c181df28
> >> no locks held by rcu_kthread/6.
> >
> > Does the following patch help?
> >
> > Thanx, Paul
> >
> > ------------------------------------------------------------------------
> >
> > commit 70ce43253a4465211a9c51e33d56a417c759a718
> > Author: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> > Date: Wed Jan 12 14:18:11 2011 -0800
> >
> > rcu: avoid pointless blocked-task warnings
> >
> > If the RCU callback-processing kthread has nothing to do, it parks in
> > a wait_event(). If RCU remains idle for more than two minutes, the
> > kernel complains about this. This commit changes from wait_event()
> > to wait_event_interruptible() to prevent the kernel from complaining
> > just because RCU is idle.
> >
> > Reported-by: Russell King <rmk@arm.linux.org.uk>
> > Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> >
> > diff --git a/kernel/rcutiny.c b/kernel/rcutiny.c
> > index 0344937..0c343b9 100644
> > --- a/kernel/rcutiny.c
> > +++ b/kernel/rcutiny.c
> > @@ -189,7 +189,8 @@ static int rcu_kthread(void *arg)
> > unsigned long flags;
> >
> > for (;;) {
> > - wait_event(rcu_kthread_wq, have_rcu_kthread_work != 0);
> > + wait_event_interruptible(rcu_kthread_wq,
> > + have_rcu_kthread_work != 0);
> > morework = rcu_boost();
> > local_irq_save(flags);
> > work = have_rcu_kthread_work;
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at http://vger.kernel.org/majordomo-info.html
> > Please read the FAQ at http://www.tux.org/lkml/
>
> Hello Paul,
> here it helps. Tested on Devkit8000 (omap3, beagleboard clone). Without
> this patch I had permanent crashes. With this patch board is running.
>
> Tested-by: Thomas Weber <weber@corscience.de>
Thank you, Thomas!!! I have added your Tested-by.
Thanx, Paul
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: INFO: task rcu_kthread:6 blocked for more than 120 seconds.
2011-01-12 22:22 ` Paul E. McKenney
2011-01-13 15:17 ` Thomas Weber
@ 2011-01-13 20:05 ` Russell King
2011-01-13 20:41 ` Paul E. McKenney
1 sibling, 1 reply; 6+ messages in thread
From: Russell King @ 2011-01-13 20:05 UTC (permalink / raw)
To: Paul E. McKenney; +Cc: Linux Kernel List
On Wed, Jan 12, 2011 at 02:22:19PM -0800, Paul E. McKenney wrote:
> Does the following patch help?
Yes it does, thanks.
Tested-by: Russell King <rmk+kernel@arm.linux.org.uk>
> commit 70ce43253a4465211a9c51e33d56a417c759a718
> Author: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> Date: Wed Jan 12 14:18:11 2011 -0800
>
> rcu: avoid pointless blocked-task warnings
>
> If the RCU callback-processing kthread has nothing to do, it parks in
> a wait_event(). If RCU remains idle for more than two minutes, the
> kernel complains about this. This commit changes from wait_event()
> to wait_event_interruptible() to prevent the kernel from complaining
> just because RCU is idle.
>
> Reported-by: Russell King <rmk@arm.linux.org.uk>
Please add '+kernel' in there, thanks.
--
Russell King
Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/
maintainer of:
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: INFO: task rcu_kthread:6 blocked for more than 120 seconds.
2011-01-13 20:05 ` Russell King
@ 2011-01-13 20:41 ` Paul E. McKenney
0 siblings, 0 replies; 6+ messages in thread
From: Paul E. McKenney @ 2011-01-13 20:41 UTC (permalink / raw)
To: Russell King; +Cc: Linux Kernel List
On Thu, Jan 13, 2011 at 08:05:26PM +0000, Russell King wrote:
> On Wed, Jan 12, 2011 at 02:22:19PM -0800, Paul E. McKenney wrote:
> > Does the following patch help?
>
> Yes it does, thanks.
>
> Tested-by: Russell King <rmk+kernel@arm.linux.org.uk>
>
> > commit 70ce43253a4465211a9c51e33d56a417c759a718
> > Author: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> > Date: Wed Jan 12 14:18:11 2011 -0800
> >
> > rcu: avoid pointless blocked-task warnings
> >
> > If the RCU callback-processing kthread has nothing to do, it parks in
> > a wait_event(). If RCU remains idle for more than two minutes, the
> > kernel complains about this. This commit changes from wait_event()
> > to wait_event_interruptible() to prevent the kernel from complaining
> > just because RCU is idle.
> >
> > Reported-by: Russell King <rmk@arm.linux.org.uk>
>
> Please add '+kernel' in there, thanks.
Done! FWIW, I copied the original from my email agent.
Thanx, Paul
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2011-01-13 20:41 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2011-01-12 17:43 INFO: task rcu_kthread:6 blocked for more than 120 seconds Russell King
2011-01-12 22:22 ` Paul E. McKenney
2011-01-13 15:17 ` Thomas Weber
2011-01-13 15:42 ` Paul E. McKenney
2011-01-13 20:05 ` Russell King
2011-01-13 20:41 ` Paul E. McKenney
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